A  13.4',  35 


[.KMHll   All- 


U.  S.  DI-PARTMFNT  OF  AGRICULTURE, 

BUREAU  OF  PLANT  INDUSTRY     Circular  No. 
B.  T.  >;  VLLOWAY,  Chief  of  Bureau. 


Tin;  PRESENT  STATUS  OF  THE  WHITE- 
PINE  BLIGHTS. 


PERLEY.   SPAlI.DiXu. 
Pathologist,   Investigations  i\   Forest  Patjhologi 


&87     <<■> 


WASHINGTON    [  GOVlRt.MENT  PRINTING  OFFIC 


o 


^  UNIV  OF  FL  LIB 
DOCUMENT^  DFP 


OEPC 


BIREAI     OF   PLANT   INDUSTRY 


Chief  of  Bureau,  Bevekly  T.  Galloway. 
Assistant  Chief  of  Bureau,  ALBERT   F.  WOODS. 
Editor,  J.  E.  Rockwell 
Cliiif  Clerk,  James  E.  Jones. 


[Cir.  35] 
2 


i  ) 


II.   P,   I         N. 


THE  PRESENT  STATUS  OF  THE  W 
PINE  BLIGHTS." 


INTRODUCTION. 

During  the  j >a^t  four  or  five  years  there  have  been  many  complaints 
from  owners  of  timber  lands  concerning  a  blight  of  while  pine  (Pinus 
stroh us  L.).  These  complaints  began  in  1904  and  have  become  increas- 
ingly frequent  ever  since.  While  there  is  some  foundation  for  alarm 
it  is  undoubtedly  true  that  thesame  amount  of  damage  fifteen  years 
ago  would  hardly  have  excited  comment.  The  price  of  timber  has 
advanced  during  this  period  and  people  generally  are  becoming  au are 
that  a  timber  shortage  is  imminent. 

The  original  stand  of  white-pine  trees  is  exhausted  and  the  [umber 
trade  can  depend  only  en  the  scrubby  sec, ml  growth,  which  is 
usuallj  less  than  75  years  of  age.  Tins  has  led  to  the  planting  of 
young  trees  in  very  considerable  quantities,  in  the  hope  of  supplying 
the  future  more  urgent  demand  at  an  adequate  profil  on  the  invest- 
ment. The  handling  of  the  young  trees  either  in  the  nursery  or  in 
the  permanent  plantation  has  led  to  a  mueh  more  intelligent  and 
careful  consideration  of  the  factors  controlling  the  growth  and  life  of 
this  species  than  was  the  ease  only  a  few  years  since.  However, 
much  is  yet  to  1>('  accomplished  in  t  his  regard,  not  only  with  the  white 
pine  hut  with  many  other  less  esteemed  species  of  our  forest  tree-. 

"  This  circular  presents  the  results  of  investigations  on  the  white  pineblighl  to  date. 
its  thai  there  are  8C\  eral  distinct  diseases  due  to  as  many  differenl  causes.  I  om- 
paratively  few  trees  have  been  killed  ami  timber  owners  Bhould  not  become  undul) 
alarmed,  a-  the  trees  have  in  many  cases  already  partially  recovered  from  the  blight. 
At  present  there  is  absolutely  no  reason  known  for  cutting  or  disposing  of  thrifty  young 
white-pine  forests  in  which  an  ted  with  the  blight  in  any  of  its 

forms;  nor  should  work  upon  pi  posed  plantations  of  this  species  be  relinquished  or 
postponed  From  fear  <>i'  this  trouble.  Studies  on  the  relation  of  insects  t<>  twig-blight 
have  been  carried  on  by  l>r.  A.  I».  It>|>kins^jf  the  Bureau  of  Entomology,  and  his 

mi-.     The  writer  and  1  >".  t<>r  ll"pkin-ha  ma<le  -om perative  studies 

in  the  field.     I?.  T.  Gallon  \'> .  ' 

•    35] 


4  PRESENT    STATUS    OF    THE    WHITE-PINE    BLIGHTS. 

HISTORY  OF  THE  DIFFERENT  FORMS  OF  BLIGHT. 

Specimens  of  diseased  twigs  were  referred  to  the  Bureau  of  Plant 
Industry  at  various  times  before  the  writer  took  up  the  problem. 
The  correspond ci ice  shows  that  a  number  of  fungi  were  found  on  the 
dead  leaves,  the  more  common  ones  being  Septoria  spadicea  Patterson 
and  Charles,"  Hendersonia  foliicola  (Berk.)  Fckl.,  Lophodermium 
pinastri  (Shrad.)  Cher.,  L.  brachysporum  Rostr.,  and  Pestalozzia 
funerea  Desm. 

In  1907  the  complaints  were  renewed  with  increasing  insistence 
and  specimens  of  affected  leaves  and  twigs  were  received  from  many 
sections  of  New  York  and  New  England.  Accordingly,  in  August, 
1907,  the  writer  was  detailed  to  study  the  problem  carefully.  Exami- 
nation of  the  specimens  of  diseased  leaves  showed  that  the  fungus 
Septoria  spadicea  Patterson  and  Charles  practically  always  accom- 
panied the  disease.  In  November,  1907,  plots  of  labeled  trees  were 
established  at  Westbury  (Long  Island),  N.  Y.;  Windsor,  Conn.; 
Brunswick,  Me.;  Exeter  and  Nashua,  N.  H.;  and  Burlington,  Vt. 
Each  tree  was  given  a  number,  and  one  hundred  or  more  trees  were 
included  in  each  plot,  except  the  one  at  Windsor,  Conn.,  where  there 
were  but  fifty.  Later,  the  plot  at  Exeter,  N.  H.,  was  discontinued, 
so  that  finally  600  trees  were  kept  under  observation.  At  various 
times  careful  notes  have  been  made  on  the  condition  of  the  foliage  of 
these  trees,  thus  furnishing  a  history  of  the  progress  of  the  disease  on 
the  labeled  trees. 

COMPLEX  NATURE  OF  THE  DISEASED  CONDITION. 

At  the  very  outset  it  was  recognized  that  there  was  more  than  one 
disease  which  was  included  in  the  term  "white-pine  blight,"  and  this 
has  become  increasingly  evident  with  the  further  progress  of  the 
investigations.  In  1907  the  disease  discussed  later  in  this  circular 
under  the  name  "leaf-blight"  was  by  far  the  most  common  one  and 
was  usually  the  one  referred  to  by  correspondents  and  forest  owners; 
but  there  was  also  found  a  twig-blight  caused  by  Lophodermium 
brachysporum  Rostr.  which  was  fairly  common,  though  not  notice- 
able in  destructive  effects.  Some  cases  were  also  noted  where  winter- 
killing might  have  occurred,  though  this  could  not  be  definitely 
ascertained. 

a  This  fungus  has  been  confused  with  Septoria  parasitica  Hartig,  but  is  quite  distind . 
A  technical  description  by  Mrs.  Flora  W.  Patterson  and  Miss  Vera  K.  Charles  follows: 

Septoria  spadicea  Patterson  and  Charles. 

Pycnidia  not  spot  forming,  late  becoming  slightly  erumpent  on  inner  surface 
of  browning  needles,  scattered,  membranous,  fuscous-olivaceous,  subimmersed, 
190-225/1  in  diameter.  Spores  hyaline,  cylindrical,  slightly  curved  or  flexuous,  apex 
acute,  one  septate,  rarely  constricted  at  septum,  3-4  X  30-45  /(.     Basidia  short. 

( )n  leaves  of  Pinus  strobus. 
[Cir.  35] 


PRESENT    BTATU8    OF    THE    WHITE-PINK    BLIGHTS.  :> 

In  L908  a  still  greater  diversity  of  forms  of  disease  was  found  and, 
in  some  sections  al  least,  the  leaf-blighl  which  had  been  so  prevalenl 
the  preceding  season  was  qoI  the  disease  which  was  then  arousing 
attention.  The  leaf-blight  was  less  prevalenl  and  apparently  much 
less  virulent  than  in  1907,"  although  it  still  had  about  the  same  dis- 
tribution. The  trouble  which  attracted  attention  in  most  localities, 
however,  was  a  twig-blight  and  uot  the  leaf-blight.  Examinations 
made  in  New  Y'ork  and  New  England  showed  that  this  twig-blighl 
was  caused  by  several  distinct  factors.  <  >ne  type  of  this  blight  was 
found  t'>  he  largely  localized  on  one  side  of  the  affected  trees,  and  it 
was  concluded  thai  this  was  a  case  of  true  winterkilling.6  Studies 
made  by  the  pathologist  of  the  Maine  Agricultural  Experiment  Sta 
1 1  mii  seem  to  show  t  hat  much  of  the  blight  in  Maine  was  due  to  winter- 
killing. This  was  not  true  of  all  sections,  however.  Besides  the 
several  forms  of  blight  ahead}  mentioned,  an  additional  one  appeared 
in  certain  localities  which  is  apparently  caused  l>\  insects. 

I  EAF-BLIGHT. 

I'l  SCRIPTION    OF    LEAF-BLIGHT. 

Leaf-blight  is  characterized  by  the  death  of  the  apical  portion  of 
the  leaf,  commonly  for  a  fourth  or  a  third  of  the  entire  length  of  the 
leaf,  hut  in  extreme  caves  finally  extending  to  the  base  ami  causing 
the  premature  fall  of  the  deadened  leaves. 

When  first  attacked,   the  Color  of  the  dead   parts    is  bright    reddish 

brow  n,  different  from  the  color  assumed  in  any  other  disease  known 
to  the  writer.  It  is  at  this  stage  that  the  disease  attracts  the  most 
attention,  as  the  reddish  color  shows  conspicuously  against  the  dark 
green  of  the  healthy  trees.  In  two  or  three  months  the  color  fades  to 
;i  dull  brownish  graj  .  at  which  stage  it  is  quite  difficult  to  dist inguish 
the  diseased  trees  from  the  healthy  ones  at  a  little  distance.  This 
change  in  color  gives  the  impression  that  the  trees  have  partially 
recovered  from  the  trouble  unless  a  close  examination  is  made.  The 
dead  portions  sometimes  break  off  during  the  winter,  but  are  usuallj 
intact   the  next  spring  and  summer. 

The  leaves  of  the  diseased  tree  may  1 f  normal  length,  or  they 

ina_\  be  much  shorter  than  normal,  and  the  same  variations  occur  in 

the  length  of  the  leaves  of  unalfeeted  trees,  i.  <■..  the  blight   serins  to 

have  no  relation  to  the  length  of  the  leaves  except  in  the  lasl  stages 

of  the  disease,   w  hell   t  he  lea\  es  are  Very  short  . 


"  DaiKi,  s.  T.     Unnumbered  circular  of  1     -    I  e  on  "  Extent  and  Impor- 

tanceof  the  White  Pine  Blight,"  pp.  1    I.     1908 

1  Galloway,  B.  T,     Rep  ef  of  Bureau  of  Plant  Industry,  p.  21.     1908 

i  Morse,  W.  .1-     Report,  Maine  Forest  Commission,  vol.  7,  pp.  20  25,   L908,  and 

Bulletin  164,  Maine  Agricultural  Experiment  Station,  pp.  21  2S,  1909 
[Clr.35] 


6  PKESENT    STATUS    OF    THE    WHITE-VINE    BLIGHTS. 

The  white  pine  ordinarily  sheds  its  leaves  in  their  second  autumn, a 
although  it  is  not  uncommon  for  them  to  persist  until  the  third  sum- 
mer and  autumn.  Usually  the  tree  has  but  two  sets  of  leaves  and 
one  or  both  may  be  affected  with  the  leaf-blight.  The  disease  may 
affect  the  whole  crown  or  only  a  portion  of  it.  Usually  the  blight 
is  generally  distributed  throughout  the  entire  crown  of  the  tree,  but 
many  cases  occur  where  the  upper  part  is  diseased  while  the  lower 
branches  are  healthy.  On  the  contrary,  the  blight  sometimes  affects 
the  lower  branches  and  the  upper  part  of  the  crown  is  still  healthy, 
but  single  diseased  branches  scattered  here  and  there  among  the 
healthy  ones  never  occur  with  this  trouble. 

The  leaf-blight  has  been  observed  by  the  writer  on  trees  of  all 
ages,  from  four  years  upward.  It  attacks  young  and  old  almost 
indifferently  when  the  comparative  numbers  of  each  are  considered. 
Trees  in  thick  stands  are  apparently  as  likely  to  be  affected  as  those 
standing  in  the  open.  As  alreatly  indicated,  an  affected  tree  is  apt 
to  be  generally  diseased  in  all  parts  of  its  crown.  Such  trees  are 
usually  found  singly  or  in  twos  or  threes  among  their  fellows  and 
often  healthy  and  affected  trees  in  all  stages  of  disease  stand  side  by 
side,  and  even  with  their  bases  growTn  together.  But  forked  trees 
may  or  may  not  have  both  parts  diseased. 

The  disease  appears  on  the  new  leaves  about  the  time  they  reach 
full  length,  beginning  in  1907  and  1908  about  Julv  1.  It  attacks  the 
leaves  only  during  their  first  summer. 

DISTRIBUTION    OP    LEAF-BLIGHT. 

The  leaf-blight  is  known  to  extend  from  the  southern  part  of  Maine 
and  northern  New  Hampshire  and  Vermont  to  the  Hudson  Valley  in 
New  York,  central  Pennsylvania,  and  along  the  Alleghenies  to  west- 
ern North  Carolina.  Whether  it  occurs  in  the  western  portion  of 
the  white-pine  region  is  as  yet  uncertain.  In  the  sections  where  it  is 
present  it  is  distributed  locally,  there  being  areas  free  from  it,  while 
other  areas  are  seriously  infested.  It  apparently  does  not  occur  at 
the  higher  altitudes  in  the  north,  as  it  has  not  yet  been  found  in  the 
Adirondacks,  where  white  pine  is  fairly  common  and  is  being  planted 
in  large  areas. 

POSSIBLE    CAUSES    OP    LEAF-BLIGHT. 

Dry  weather,  resulting  in  an  insufficient  supply  of  water  in  early 
summer,  would  seem  to  cause  the  death  of  leaves  in  this  manner,  but 
observations  seem  to  show  that  this  can  not  be  the  cause  of  the  leaf- 
blight.  A  tree  about  20  inches  in  diameter  and  which  is  in  good  con- 
dition otherwise,  standing  beside  a  reservoir  of  water  which  has  not 


"  Sargent,  C.  S.     Manual  of  Trees  of  North  America,  p.  4.     1905. 
[Cir.35] 


PBE8ENT    STATUS    OF    THE    WHITE-PINE    BLIGHTS.  7 

beenempt}  for  the  last  fifteen  years,  is  nevertheless  affected  generally 
throughout  the  top  with  leaf-hlight.  Other  similarly  situated  frees 
in  other  localities  show  the  same  condition. 

Winter  injurj  is  still  an  unsettled  question,  It  would  seem  thai 
trees  which  were  affected  by  winterkilling  in  the  roots  during  the  la>t 
two  or  three  winters  would  show  the  effects  more  plainly  during  the 
past  extremel)  dry  summer  (1908),  rather  than  a  partial  recovery,  as 
was  actually  the  case  with  50  per  cent  of  the  diseased  trees  which 
have  been  under  careful  observation.  In  other  words,  the  affected 
trees  have  been  recovering  during  the  driest  summer  that  has  been 
experienced  for  many  year-.  There  is  another  form  of  winter  injury 
which  is  essentially  a  drying  out  of  the  tissue  due  to  continued  trans- 
piration from  the  leaves  when  the  soil  and  roots  are  frozen.  This  is 
a  common  cause  of  deal  h  of  conifiers  in  t  he  ( treat  Plains  region  of  the 
West  and  ha-  affected  the  while  pine  in  certain  districts  of  the  Bast, 
as  has  been  slated  in  other  parts  of  this  circular. 

The  late  freeze  in  the  spring  of  1907  might  have  killed  the  tips  of 
the  leave-  of  the  while  pine,  hut  growth  at  that  time  was  hardly 
more  than  begun.  Moreover,  observations  made  by  the  writer  upon 
the  freeze  "I'  -lime  :;.  1908,  showed  thai  the  white  pine  was  not  in- 
jured in  i  he  Adirondack-,  although  other  native  trees  were  fro /ami  and 
immediately  showed  the  effects  of  freezing.  The  white  pine  was  eon- 
spicuouslj  free  from  leaf-bhghl  throughout  the  season,  as  it  always 

ha-  keen   in   the  Adirondack   region,   where   both  early   and   late  frosts 

arc  very  prevalent. 

Sun-scald  would  affecl  the  tree  top  more  or  less  locally  on  one  side, 
a-  i-  described  by  Stewart"  a-  occurring  on  cherry,  an. I  by  Stone 
and  Smith  b  on  sugar  maple,  whereas  such  i-  not  the  case.  The  dis- 
ease occurs  ireneralk  throughout  the  tree  top  or  in  the  entire  upper 
or  lower  port  ion  of  i  he  top;  the  leaf-blight  is  not  localized  on  one  side 
of  the  tree.  I  low  ever,  t  he  leaf-blight  appears  at  the  time  when  sun- 
scald  would  seem  to  be  most  likely  to  affect  the  white  pine  just  as 
the  new  leaves  reach  their  full  length. 

[njurious  gases  can  hardly  he  the  cause  of  leaf-blight,  as  the  disease 
occurs  in  localities  far  from  any  considerable  source  of  smoke  or 
sulphur  gases. 

Aeration  can  have  nothing  to  do  with  the  death  of  the  tips  of 

leaves,  a-  the  disease  occurs  on  trees  in  open  ground,  as  well  as  on 
those  in    close    stands  where    there    i-    a    thick    layer   of   dead    needles 

covering  t he  root-. 

.■..in  .1    C.     Bulletin  162,  New  York  (I  ieneva)  Agricultural  Experiment  Station, 
pp.  171    178 

b  Stone,  G  E.,  and  Smith,  It.  E.  Report  9,  Massachusetl  (Hatch)  Agricultural 
Experiment  Station,  141.  81-82.     I  - 

35J 


8  PRESENT    STATICS    OF    THE    WHITE-PINE    BLIGHTS. 

Root-rot  can  not  apparently  produce  such  a  trouble  as  leaf-blight, 
as  a  considerable  number  of  white-pine  trees  have  been  examined  by 
the  writer  which  had  their  roots  largely  killed  by  Fomes  annosus  (Ft.) 
Cke.,  but  their  leaves  were  green  for  their  whole  length,  and  in  fact 
showed  no  disease,  although  the  roots  were  so  badly  rotted  that  the 
trees  were  blown  over.  Clinton  a  has  described  diseased  trees  which 
had  a  fungus  on  the  roots,  but  he  was  uncertain  whether  the  fungus 
killed  the  roots  or  not.  In  this  case  the  tree  top  died  downward 
gradually. 

As  before  mentioned,  a  number  of  fungi  have  been  found  fruiting 
on  the  needles  affected  with  leaf-blight.  These  are  Septoria  spadicea 
Patterson  and  Charles,  Hendersonia foliicola  (Berk.)  Fckl.,  Pestalozzia 
funerea  Desm.,  and  a  number  of  others  which  are  known  to  occur  only 
on  dead  tissues.  Of  all  these  only  the  first  has  been  found  occurring 
at  all  regularly  on  the  diseased  parts.  Inoculations  have  been  made 
by  the  writer  on  young  white  pines  in  the  greenhouse,  but  no  infection 
resulted.  This  proves  nothing,  as  the  leaves  of  the  inoculated  plants 
were  not  young  and  newly  grown,  which  condition  may  be  necessary 
for  the  attack  of  the  fungus.  Also,  other  conditions  necessary  for  the 
growth  of  the  fungus  might  not  have  been  obtained  in  the  experiments. 
Septoria  spadicea  Patterson  and  Charles  has  not  been  found  so  gener- 
ally accompanying  the  disease  in  1908  as  was  the  case  in  1907,  but 
this  may  possibly  be  explained  by  the  extremely  dry  season  of  1908, 
which  might  have  hindered  the  development  of  fruiting  bodies. 

It  is  impossible  to  definitely  state  what  is  the  primary  cause  of 
the  leaf-blight,  but  it  probably  is  closely  connected  with  extreme 
climatic  conditions  which  have  prevailed  during  the  past  few  winters. 

During  the  past  two  years  there  has  been  considerable  mention  of  a 
disease  of  larch  and  Abies  pectinata  in  Scandinavia  and  France.  This 
disease  was  characterized  by  the  reddening  and  ultimate  death  of  the 
leaves  quite  generally  throughout  the  top  of  the  arTected  tree.  A 
number  of  different  fungi  have  been  found  by  various  investigators 
associated  with  the  disease,  but  proof  of  their  parasitic  character  was 
in  most  cases  not  obtained.  The  outbreak  simultaneously  in  Europe 
and  America  of  a  somewhat  similar  disease  on  closely  related  trees  is 
at  least  interesting,  and  it  is  barely  possible  that  they  are  both 
primarily  due  to  extreme  weather  conditions,  which  are  not  thoroughly 
understood  at  present  in  either  locality. 

RESULTS    OP   INVESTIGATIONS    OF   LEAF-BLIGHT. 

The  leaf-blight  has  been  known  for  a  number  of  years  and  several 
wood-lot  owners  say  they  have  known  it  for  ten  or  more  years.  The 
outbreaks  usually  begin  about  July  1  and  vary  in  intensity  from  year 

«  Clinton,  <i.  P.     Report,  Connecticut  State  Botanist  for  1906,  pp.  320-321. 
[Cir.35] 


PRESENT    STATUS    OF    THE    WHITE-PINE    BLIGHT8.  9 

to  year,  that  "!'  1907  being  especially  bad,  while  in  1908  it  was  much 
less  serious. 

The  leaf-blighl  may  cause  the  death  of  affected  trees.  In  a  few 
instances  ii  has  been  known  t<>  do  so  in  a  single  season,  but  ii  usually 
lakes  two  or  more  seasons.  Even  in  the  worsi  affected  districts  the 
number  of  trees  killed  is  relatively  small,  so  the  damage  is  one  thai  is 
negligible,  for  the  present  a1  least.  Our  records  show  that  the  di 
was  much  less  virulent  in  1908  than  in  1907;  thai  no  new  trees 
became  affected  in  1908;  thai  many  of  the  tree-  thai  were  affected  in 
1907  were  also  diseased  in  I908;and  thai  50  per  cenl  which  were  dis- 
eased in  1907  did  nol  have  their  1908  leaves  affected  and  are  thus 
showing  a  partial  recover}  from  the  trouble.  The  status  of  the 
trouble  is  generally  much  more  encouraging  than  it  was  in  1907. 

TWIG-BLIGHT. 

Iii  1907  the  leaf-blight  previously  described  was  found  to  be  the 
prevalent  white-pine  disease,  but  this  was  nol  the  case  generally  in  1908 
Except  in  localities  where  the  leaf-blight  had  been  most  prevalent 
in  the  preceding  season  a  twig-blight  was  found  to  be  most  common 
in  1908.  It  was  also  found  that  there  were  several  different  forms  or 
types  of  twig-blight,  apparently  caused  by  as  many  different  factors. 

TWIG-BLIGHT    I    VUSED    HY     WINTERKILLING. 

One  form  of  twig-blight  in  which  the  injury  was  usually  limited  to 
the  north  and  west  sides  of  the  trees,  while  the  opposite  sides  were 
uninjured,"  was  prevalent  in  Maine.  Sometimes  the  entire  tree  was 
affected,  bul  this  was  rather  uncommon.  This  blight  affected  only 
small  trees,  usually  less  than  10  or  1">  feet  in  height,  while  large  trees 
were  seldom  or  onlj  slightly  blighted.  All  the  indication-  seemed 
to  show  i  hai  i  hi-  was  a  real  winter  injury,  caused  by  excessive 
transpiration  of  water  from  the  leaves  while  the  roots  were  fro/en 
solidly    in    the    earth.      The    leaf    t  i  — lies    were    thus    drained    of    their 

necessary  water  content  without  being  able  t<»  replace  it  from  the 
roots  and  of  course  died  from  lack  of  water.  Aside  from  the  rela- 
tively small  number  of  trees  which  were  entirely  killed  the  damage 
was  \  er\  slight,  amounting  at  most  to  a  setback  in  growth  for  a  year 
or  possibly  two  \  ears. 

TWIG-Bl  ICHT  CAUSED    B1     INSEl  TS. 

Another  twig-blight  was  studied  more  especially  in  New  Hamp- 
shire by  the  Bureau  of  Entomology  of  t  he  Depart  ineni  of  Agricull  ure. 
It  was  characterized  by  t he  wilting  and  death  of  the  previous  year's 

■  Morse,  \\    .1      Report,  Maine  Forest  Commis  ion,  vol.  7,  pp.  20  25,  L908,  and  Bul- 
letin L64,  Maine  Agricultural  Experimi  u,  pp.  21-28,  1909. 
[Clr.  35] 


10  PRESENT    STATUS    OF    THE    WHITE-PINE    BLIGHTS. 

growth  on  the  lateral  branches  on  all  sides  of  the  trees  in  April  and 
May,  1908.  The  leader  or  central  shoot  was  very  rarely  affected. 
This  type  of  twig-blight  was  apparently  caused  by  insects,  and  is 
mentioned  here  to  differentiate  it  from  the  other  forms  of  blight. 
This  blight  was  found  in  the  more  northern  part  of  Maine  also,  but 
not  in  the  belt  of  lower  altitude,  including  the  well-settled  region 
near  the  coast,  where  t he  winterkilling  previously  mentioned  seemed 
to  be  especialty  prevalent. 

TWIG-BLIGHT   CAUSED    BY    LOPHODEEMIUM    BRACHYSPORUM . 

The  twig-blight  caused  by  Lophodermium  brachysporuiri  Rostr. 
was  noted  more  especially  at  Brunswick,  Me.,  in  a  small  tract  of  young 
trees  from  1  to  about  10  feet  in  height  which  was  located  on  the  edge 
of  an  older  stand  and  thus  at  a  disadvantage  by  being  overshadowed. 
Here  some  damage  was  done,  a  considerable  number  of  the  young 
trees  being  killed  outright.  The  disease  was  also  noted  on  the  lower 
branches  of  older  trees,  not  only  at  Brunswick  but  also  sparingly  at  a 
number  of  other  stations. 

SENSITIVE  NATURE  OF  THE  WHITE  PINE. 

Among  all  our  native  forest  trees  the  young  white  pine  is  especially 
liable  to  serious  and  permanent  injury  from  wounds  which  are  almost 
of  a  trivial  nature.  If  a  branch  or  j'oung  tree  becomes  sharply  bent 
without  any  external  indications  of  breakage  it  is  almost  sure  to  die 
from  the  effects  of  the  undue  strain.  Many  trees  which  have  a  com- 
paratively small  wound,  extending  less  than  one-third  the  circum- 
ference of  the  stem,  die  from  the  effects  of  such  wounds.  This  is 
especially  true  of  small  trees.  The  white  pine,  too,  is  said  to  be  par- 
ticularly susceptible  to  injury  from  poisonous  gases  and  smoke. a 
These  statements  must  not  be  taken  as  an  argument  against  planting 
•the  white  pine,  as  its  many  valuable  properties  far  outweigh  any 
sensitiveness  to  injury  while  young. 

DEATH  OF  WHITE-PINE  TREES    FROM  OTHER  CAUSES  THAN 

BLIGHT. 

COMPETITION. 

In  any  fairly  dense  stand  of  trees  it  is  inevitable  that  some  of  them 
will  die  unless  thinning  is  properly  done;  it  is  perfectly  natural  that 
some  should  die  from  various  causes.  The  most  potent  factor  in  the 
death  of  such  trees  is  competition  among  the  I  ices  themselves.  There 
is  a  very  keen  competition  among  the  roots  for  food,  water,  and 
space  in  the  soil.     There  is  an  equally  sharp  competition  among  the 

"  Schrenk,  Hermann  von,  and  Spaulding,  Perley.     Bulletin  149,  Bureau  of  Plant 
Industry,     1909. 
[Cir.  35  | 


PRESENT    STATUS    OF    THE    WHITE-PINE    BLIGHTS.  11 

terminal  shoots  and  lateral  branches  for  light  and  sunshine,  which 
results  in  the  most  vigorous  trees  gaining  the  lead  and  keeping 
slighthj  ahead  ever  after  if  no  accident  happens  t<>  prevent.  This 
results  in  the  weaker  trees  being  placed  at  a  constantly  increasing 
disadvantage,  and  finally  being  crowded  out  of  the  race,  suppressed, 
and  nit imately  killed. 

I  \-l   (IS. 

It  has  been  shown  l>\  the  entomologists  thai  insects  are  responsi- 
ble for  the  death  of  t  rees  of  all  ages  and  that  they  often  cause  injuries 
to  the  leaves,  tun:-,  and  branches  which  are  of  more  or  less  serious 
consequence.  There  are  also  certain  troubles  affecting  the  living 
trees  in  which  it  is  \  ery  difficull  to  determine  whether  or  not  insects 
or  fungi  are  the  primary  cause  or  whether  it  is  a  combination  of 
factors,  including  insects,  diseases,  climate,  etc. 

ROOT-ROT. 

There  areseveral  different  fungi  which  cause  root-rot  and  it   is  by 

no  means  an  uncommon  thing  to  find  tree-  killed  in  this  way.  The 
two  fungi  which  are  found  most  commonlj  causing  root-rot  are 
Ariiiilhiriii  meUea  (Vahl.)  Quel,  and   Fomes  annosus  (Fr.)  Cke. 

I   Kill  I  \  [NG. 

Lightning  also  kills  scattered  trees  and  groups  of  trees,  and  the 
loss  from  this  source  may  not  be  as  insignificanl  as  it  is  now  sup- 
pi  >sei  I  to  be. 

CAUTION. 

All  of  the  factor-  mentioned  competition  among  the  trees  for 
food,  water,  etc.;  injuries  caused  by  insects,  root-rot,  and  light- 
ning are  constantly  causing  the  death  of  white-pine  trees,  and  the 
timber  owner  must  be  careful  not  to  come  to  the  conclusion  that  all 
dead  tree-  are  caused  by  the  blight.  The  blight  does  kill  trees,  but 
the  damage  thus  far  caused  by  it  is  not  great,  and  apparently  will 
not  become  a  serious  matter  in  most  localities. 

CONCLUSIONS. 

The  white-pine  blight  i-  a  complex  of  several  different  diseases. 

The  leaf-blighl  is  the  disease  which  bas  persisted  longest  in  many 
localities,  [ts  cause  is  as  yet  undetermined.  It  was  much  less  preva- 
lent in  1908  than  in  1907  and  man)  affected  trees  have  partially 
recovered,  while  no  new  one-  became  diseased.  This  is  believed  to 
be  t  he  mi  >st  important  form  of  blight . 

The  twig-blighl  caused  l>\  Lophodermium  may  occur  another  sea- 
son if  the  weather  is  especially  favorable  for  the  fungus,  bul  serious 

[Cir.3o] 


!  12  PRESENT    STATUS    OF    THE    WHITE-PINE    BLIGHTS. 

jj*  damage  from  this  disease  is  not  at  all  common.  The  other  twig- 
ico  blights  arc  transitory  in  character  and  have  thus  far  caused  no 
§o>  permanent  damage.  Any  or  all  of  them  may  not  occur  again  in 
!o  the  next  ten  years,  and  they  may  recur  within  one  or  two  years, 
|to  though  this  is  not  likely.  The  total  damage  caused  by  the  blight  is 
i<f  comparatively  slight,  only  scattering  trees  having  yet  been  killed. 
1*°  Trees  die  constantly  from  the  effect  of  competition  among  them- 
|  selves,  from  the  attacks  of  insects,  from  root-rot,  and  from  lightning, 
and  the  timber  owner  must  be  careful  not  to  confuse  trees  killed  in 
this  way  with  those  killed  by  the  blight. 

Those  trees  which  are  so  badly  diseased  as  to  be  unable  to  recover 
ought  to  be  cut  and  utilized,  for  the  same  reasons  that  any  dying 
tree  should  be  removed  from  the  forest.  There  is  absolutely  no 
reason  known  at  present  for  cutting  trees  that  are  able  to  recover 
or  that  are  healthy. 

Approved: 

James  Wilson, 

S<  cretary  of  Agriculturt . 

Washington,  1).  ('..  June  8,  1909. 

[Cir.  3.5] 

o 


